// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
// Distributed under the MIT License (http://opensource.org/licenses/MIT)

#pragma once

#ifdef _WIN32
#error include tcp_client-windows.h instead
#endif

// tcp client helper
#include <spdlog/common.h>
#include <spdlog/details/os.h>

#include <arpa/inet.h>
#include <netdb.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <sys/socket.h>
#include <unistd.h>

#include <string>

namespace spdlog {
namespace details {
    class tcp_client
    {
        int socket_ = -1;

    public:
        bool is_connected() const { return socket_ != -1; }

        void close()
        {
            if (is_connected())
            {
                ::close(socket_);
                socket_ = -1;
            }
        }

        int fd() const { return socket_; }

        ~tcp_client() { close(); }

        // try to connect or throw on failure
        void connect(const std::string& host, int port)
        {
            close();
            struct addrinfo hints
            {
            };
            memset(&hints, 0, sizeof(struct addrinfo));
            hints.ai_family = AF_UNSPEC;      // To work with IPv4, IPv6, and so on
            hints.ai_socktype = SOCK_STREAM;  // TCP
            hints.ai_flags = AI_NUMERICSERV;  // port passed as as numeric value
            hints.ai_protocol = 0;

            auto port_str = std::to_string(port);
            struct addrinfo* addrinfo_result;
            auto rv = ::getaddrinfo(host.c_str(), port_str.c_str(), &hints, &addrinfo_result);
            if (rv != 0)
            {
                throw_spdlog_ex(fmt_lib::format("::getaddrinfo failed: {}", gai_strerror(rv)));
            }

            // Try each address until we successfully connect(2).
            int last_errno = 0;
            for (auto* rp = addrinfo_result; rp != nullptr; rp = rp->ai_next)
            {
#if defined(SOCK_CLOEXEC)
                const int flags = SOCK_CLOEXEC;
#else
                const int flags = 0;
#endif
                socket_ = ::socket(rp->ai_family, rp->ai_socktype | flags, rp->ai_protocol);
                if (socket_ == -1)
                {
                    last_errno = errno;
                    continue;
                }
                rv = ::connect(socket_, rp->ai_addr, rp->ai_addrlen);
                if (rv == 0)
                {
                    break;
                }
                last_errno = errno;
                ::close(socket_);
                socket_ = -1;
            }
            ::freeaddrinfo(addrinfo_result);
            if (socket_ == -1)
            {
                throw_spdlog_ex("::connect failed", last_errno);
            }

            // set TCP_NODELAY
            int enable_flag = 1;
            ::setsockopt(socket_, IPPROTO_TCP, TCP_NODELAY, reinterpret_cast<char*>(&enable_flag), sizeof(enable_flag));

            // prevent sigpipe on systems where MSG_NOSIGNAL is not available
#if defined(SO_NOSIGPIPE) && !defined(MSG_NOSIGNAL)
            ::setsockopt(socket_, SOL_SOCKET, SO_NOSIGPIPE, reinterpret_cast<char*>(&enable_flag), sizeof(enable_flag));
#endif

#if !defined(SO_NOSIGPIPE) && !defined(MSG_NOSIGNAL)
#error "tcp_sink would raise SIGPIPE since neither SO_NOSIGPIPE nor MSG_NOSIGNAL are available"
#endif
        }

        // Send exactly n_bytes of the given data.
        // On error close the connection and throw.
        void send(const char* data, size_t n_bytes)
        {
            size_t bytes_sent = 0;
            while (bytes_sent < n_bytes)
            {
#if defined(MSG_NOSIGNAL)
                const int send_flags = MSG_NOSIGNAL;
#else
                const int send_flags = 0;
#endif
                auto write_result = ::send(socket_, data + bytes_sent, n_bytes - bytes_sent, send_flags);
                if (write_result < 0)
                {
                    close();
                    throw_spdlog_ex("write(2) failed", errno);
                }

                if (write_result == 0)  // (probably should not happen but in any case..)
                {
                    break;
                }
                bytes_sent += static_cast<size_t>(write_result);
            }
        }
    };
}  // namespace details
}  // namespace spdlog
